Elevator Feed Voltage Dips & Swells

[Jakez]

Has anyone ran into the issue below?

I have an elevator controller (by others) that is shutting the elevator down and the controller is given a fault of low leg Amps. I put a Fluke 1735 power logger meter on the line side of the controller to record any events.
This is a 480V 3Ph 3W +G feeder.

My meter shows my voltage for A phase dips to 115V for 17ms and spikes back up to 299V for 9ms. So this event lasted 26ms. This was right around the time I got the call that the elevator shutdown again. Before I start changing the breaker I really would like to make sure that the breaker is the issue. Any thoughts?

Thanks in advance.

 

[zbang]

There are a lot of other places I'd look before replacing the breaker. Sounds like you're measuring L-N or L-G voltages. For a 3ph 3W feeder, you need to look at the line-to-line voltages, not line-neutral.

Also, have you put the logger on either the line side of the elevator breaker or somewhere upstream, even the load side of the service disconnect? Did you look at current? Have you checked for loose connections? (Is this fed from a 480v service or a transformer?)

Just as a WAG, there could be another device on the same supply that's dragging the A phase down as you've observed. Maybe a heater being switched on or a bad motor somewhere else.

 

[electricianexpress]

Were you only logging one leg? Could another leg have been going up as this leg was going down? I always when a leg is going on the high side of normal (277), I am looking for a bad neutral connection. You probably don't have a neutral on this feeder but the service end neutral may have a bad connection. Before changing the breaker, log power on the line side to compare. I am very doubtful the breaker is the problem.

 

[meternerd]

Ditto on logging all three phases of both voltage phase to phase and current on each leg. You say 3W +G....does that mean the source is Wye or Delta? What's the high side of the source transformer? You need to associate a current draw vs a voltage drop to figure out what's going on. Just keep moving the recorder "back" upstream until you find the current that's dropping the voltage. You could have a primary problem on the transformer.

 

[Jakez]

I metered all phase. I used the meter to record only EVENTS that occur while the meter is on. The meter did not show any events on any other phase, only A. I also had a second meter set up on the line side of the Dist. Panel. This meter recorded NO EVENTS. I only saw this dip & Swell on the load side of the elevator breaker.